1. Field of the Invention
The present invention relates to a reversible ratchet wrench, and more particularly to a reversible ratchet wrench with a high torsion.
2. Description of the Related Art
A conventional reversible ratchet wrench 80 in accordance with the prior art shown in FIG. 12 comprises a handle 81 having an enlarged driving head 82 defining a driving chamber 83 and a retaining recess 84 connecting to the driving chamber 83, a driving member 86 secured in the driving chamber 83, a direction change device xe2x80x9cBxe2x80x9d including a retaining member 21 pivotally mounted on a pivot axle 20 and including a tooth-shaped retaining portion 210 meshing with the driving member 86, a pressing device xe2x80x9cCxe2x80x9d including a pressing member 23 urged on the positioning protrusion 211 of the retaining member 21, and a spring 24 biased between the pressing member 23 and the handle 81.
However, the conventional reversible ratchet wrench in accordance with the prior art has the following disadvantages.
1. The retaining member 21 is engaged with the driving member 86 so that the force exerted on the retaining member 21 is directly transmitted to the pivot axle 20. Therefore, when the driving member 86 is used to drive and operate a workpiece, the force is entirely concentrated on the pivot axle 20 so that the pivot axle 20 is easily worn out, thereby shortening the lifetime of the ratchet wrench.
2. The locking force exerted by the retaining member 21 on the driving member 86 is supplied by the pivot axle which can only afford a limited locking force so that when the driving member 86 is used to drive a large workpiece, the retaining member 21 cannot efficiently lock and retain the driving member 86 so that the driving member 86 easily slips on the retaining member 21, thereby causing the ratchet wrench inoperative.
3. When the user wishes to change the driving direction of the ratchet wrench, the retaining member 21 is rotated about the pivot axle 20 to move the positioning protrusion 211 which then presses the pressing member 23 inward so that the positioning protrusion 211 can be moved to and located on the other side of the pressing member 23. In such a manner, the positioning protrusion 211 is frequently engaged with the pressing member 23, thereby greatly increasing the friction therebetween so that the positioning protrusion 211 is easily worn out during long-term utilization.
In accordance with an embodiment of the present invention, there is provided a reversible ratchet wrench comprising: a handle having an enlarged driving head defining a driving chamber therein, a receiving chamber defined in the handle and located adjacent to the driving chamber, a retaining recess defined in a side wall of the driving chamber and connecting to the receiving chamber; a driving member secured in the driving chamber and having an outer wall provided with a plurality of tooth-shaped first retaining portions; and a direction control device mounted on the handle.
The direction control device includes: a direction control member rotatably mounted in the receiving chamber; a retaining member pivotally mounted in the retaining recess and having a first side provided with a plurality of tooth-shaped second retaining portions meshing with the plurality of tooth-shaped first retaining portions; a pressing member mounted between the receiving chamber and the retaining recess, the pressing member being secured on the direction control member to rotate therewith and slidably rested on a second side of the retaining member for pivoting the retaining member; and an elastic member mounted between the direction control member and the pressing member for urging the pressing member on the second side of the retaining member.
In accordance with another embodiment of the present invention, each of the second retaining portions of the retaining member has two sides each formed with a convex arcuate edge and a mediate section located between the two sides and formed with a locking edge.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.